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Tension members I


To describe the typical uses of tension members and to explain the derivation of the rules in Eurocode 3 [1].


Worked Example: Tension Members I


The lecture introduces the use of steel tension members in construction. The modes of failure of these members, especially at holes in connection zones, are discussed. The design formulae, as proposed by Eurocode 3 [1], are presented.


Structural stability depends on a balance between elements sustaining either tensile or compressive stresses. Because natural materials are more suited to resist compression, the traditional objective of the designer has been to avoid tensile stresses using ingenious systems such as arches, vaults, domes, etc. Special treatment of natural materials, however, allowed for the development of structures, usually temporary, where the tension members played a fundamental role (see Figure 1). Even in situations of fundamentally massive construction, tension elements can be found helping to stabilise the system (see Figure 2). The Industrial Revolution, during which time ferrous materials were developed, brought great advances in the use of tensile elements as pure tension could now be safely transmitted without the previous durability problems associated with natural materials.

Some simple forms of structures with tension members are given in Figure 3; these are an inclined roof with a tension beam and a truss whose bottom chord and several diagonals are in tension. More recent developments use cables as tension members in such structures as roofs, bridges, masts, cranes, etc. The present lecture deals with conventional tension members.

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